#!/bin/bash -e

# cyche-build <name> <file> <hash> [--self]
#
# (Re)build and deploy the service <name> using the docker-compose configuration
# in <file> (usually, docker-compose.yml).
#
# In the typical case, this is a straightforward process and `docker compose up`
# can properly recreate/start containers for the guest service.  However, when
# rebuilding cychedelic itself, `--self` must be given, which modifies this
# script to support self-upgrade of the running compose service.
#
# In `--self` mode, we prepare and start the cychedelic service under an
# alternate project name each time, before taking down the existing (old)
# services.  This is necessary because running `docker compose up` terminates
# old containers before starting new ones.  Termination of the ACID service
# interrupts the `compose up` process before it can start the replacements.
# Normally, `docker compose down` is then not needed.
#
# We take <hash> (from cyche-source) so we may commit it to the cache iff the
# deployment is successful.
#
# This file exits early on any failure (non-zero).  On a successful run in
# `--self` mode, this file does not exit (we are killed by `compose down`).

cd "/services/$1"

if [ "$4" == "--self" ]; then
    prev=$(cat '.git/previous_slug')
    [ -n "$prev" ] && prev="--project-name $prev"

    slug=$(echo -n "$1-"; tr -dc a-z </dev/urandom | head -c 12)
    next="--project-name $slug"
fi

docker compose $next --file "$2" pull
docker compose $next --file "$2" build \
    --force-rm \
    --no-cache \
    --pull
docker compose $next --file "$2" up \
    --detach \
    --remove-orphans \
    --force-recreate

echo "$2" >.git/previous_file
echo "$3" >.git/previous_hash

if [ "$4" == "--self" ]; then
    echo "$slug" >.git/previous_slug
    docker compose --file "$2" down
    docker compose $prev --file "$2" down
fi